The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC manufacturing and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. Such advances have increased the complexity and challenges of manufacturing of ICs. In IC manufacturing (or processing), hard mask is used to protect against loss of un-intended material(s) on the substrate during etching process. To pattern gate structures with polysilicon, a hard mask is deposited over polysilicon to prevent its loss during etching. Such hard mask needs to be removed after processing operations, such as patterning etch, implantation, wet cleaning, etc., to allow polysilicon to become either polycide (for polysilicon gate) or be replaced by another conductive metal (for replacement gate).
Removing hard mask over polysilicon has become increasingly challenging. It is within this context the following disclosure arises.